Homokinetic joints are known from U.S. Pat. No. 3,218,827. Like cardan joints, as they are known, they serve to transmit a rotary motion from a rotating part to another part driven in a rotary manner, when the axes of rotation of these two rotating parts do not coincide. Homokinetic joints consist essentially of an outer ring which is flanged to the driven part, for example the wheel of an automobile, and an inner ring, fastened to the driving part, for example the drive shaft of an automobile. The inner ring has the approximate shape of a spherical disk, so that it can turn and swivel in the outer ring, whose inner side has an approximately cylindrical shape. Grooves with approximately one-third circular cross section are provided in the outer surface of the inner ring and the inner surface of the outer ring, whereby a ball is mounted in each groove of the inner ring and the corresponding groove of the outer ring. These balls are prevented by a ball cage from falling out of the grooves, which therefore serve as ball-bearing races.
Joints of this type have the considerable advantage that in contrast to cardan joints, the driven part is not subjected to any rotary oscillation superimposed on the rotary motion, whereby such a superimposed rotary oscillation, occurring in cardan joints, is a function of the angle between the axis of the driving part and the axis of the driven part.
The grooves in the inner and outer rings, which serve as ball-bearing races, are not parallel to the axis of rotation of these rings, but are inclined at an angle to this axis. In addition, these grooves can always be inclined in the same direction. in other words parallel to one another or, alternatively, they can be inclined relative to one another, whereby the angle of inclination relative to the axis differs by some amount or is the same.
In a vertical broaching machine known from U.S. Pat. No. 3,799,030 for broaching such rings in homokinetic joints, a prismatic wedge is provided for tangential, axial, and radial immobilization of the workpiece on a workpiece holder located at the broaching location of the broaching machine, said wedge being supported on the one hand by wedge-shaped surfaces in a corresponding recess in a holding pin on the workpiece holder, and provided with an arcuate suface on its outer side, said surface fitting into a previously broached ball-bearing race, thereby guiding and immobilizing the workpiece axially, tangentially, and radially. When broaching a first pair of ball-bearing races, the prismatic wedge travels in the corresponding recess in the holding pin, with only one of its free ends engaged therein. The prismatic wedge has a surface in the vicinity of this free end which rests against the inside wall of the workpiece. These broaching machines with this workpiece holder have performed outstandingly in principle. However, the fact that tolerances for the bore in the workpiece are on the order of magnitude of several microns means that corresponding errors develop in the position of the grooves to be broached relative to the axis of symmetry of the workpiece.